ADY -Straight and Level Flight, Pilot Technique

Question 1

Remember that lift varies with the square of the velocity so

2 x the velocity = …..

3 x the velocity = …..

10 x the velocity = …..

Answer 1

4 x the lift

3 x the lift

100 x the lift

Question 1

Lift = Cl1/2pV2S

p = …..?

Answer 1

Air Density

Question 2

Double slotted fowler flaps have 3 main points, name them …..

Answer 2

1. Excellent for lift production
2. Used on heavy aircraft
3. Further extends the effects of the fowler flap

Question 3

Lift = Cl1/2pV2S

What is Cl?

Answer 3

AoA

Question 3

Split flaps have 2 main points, name them …..

Answer 3

1. High drag
2. More useful to control airspeed than for the production of lift

Question 4

Aircraft with high wing loading can achieve low speeds with …..

Answer 4

the use of sophisticated slotted flaps and slats

Question 5

Flaps are never/always used to fly for range or improve the gliding distance?

Answer 5

Never

Question 5

Flying for Max Range

• No wind -
• Head wind -
• Tail wind -
• Height -
• Increased weight -

Answer 5

• No wind - fly @ min total drag
• Head wind - Fly faster than min drag speed
• Tail wind - fly slower than the min drag speed to maximise the tail wind
• Height - Full Throttle Height (theoretical)
• Increased weight - Fly @ speed for min drag

Question 6

Lift = Cl1/2pV2S

How does the pilot control: 1/2pV2S

Answer 6

With the throttle since this represents the mass of air striking the aeroplane

Question 7

Wing Loading

Small wings + high weight =

Answer 7

High wing loading

Question 8

Slats can do 3-main things, name them …..

Answer 8

1. Can increase max Cl by up to 60%
2. Allow operations beyond the normal stalling AoA
3. Have no real effect until high AoA’s are achieved

Question 9

Lift = Cl1/2pV2S

What is S?

Answer 9

S = Max “Plan Area” of the wing

Question 11

Wing Fences do 2-main things, name them …..

Answer 11

1. Straighten the spanwise airflow near the wing tip
2. Improve performance and allow slower approach speeds

Question 11

Total drag v’s speed

If a headwind exists, the max distance per litre of fuel consumed in level flight would be achieved by flying at …..

Answer 11

a speed greater than min drag

Question 13

The lift/drag ratio will always be ….. by flap extension

Answer 13

Spoilt

Question 14

Lift = Cl1/2pV2S

What is 1/2pV2S

Answer 14

It is the Kinteic Energy formula for a unit volume of air

Remember that Kinetic Energy = 1/2MV2

Question 14

Remember that min drag always occurs at a higher/lower speed than min power

Answer 14

Always higher

Question 15

Total drag v’s speed

Weight: To use the least amount of fuel in a given distance for nil wind conditions, the aircraft must be flown at …..

Answer 15

at the best lift/drag ratio for any weight

Weight does not matter

Question 16

To achieve maximum range when a head or tail wind exists, the correct speed to use is …..

Answer 16

Higher than the best lift/drag ratio in a headwind and lower in a tail wind

Question 16

If an aircraft is maintaining level flight at a speed that produces max endurance and the speed is reduced what will happen to the power ….

Answer 16

more power will be required as the speed is reduced

Question 18

Explain how a Vortex Generator works …..

Answer 18

It works by lifting the straighting air away from the surface and re-energising the boundary layer

Question 19

Ignoring all other considerations the theoretical height to fly at in a piston engined aeroplane to achieve max range is:

Answer 19

Full throttle height

Question 20

Devices such as slats, slotted flaps, and vortex generators act to modify the behaviour of the ….

Answer 20

boundary layer

Question 22

Wing Loading:

Big wings + low weight =

Answer 22

Low wing loading

Question 23

Fowler Flaps have 2 main points, name them ....

Answer 23

1. Very good lift production 2. The slot adds extra energy to the seriously retarded airflow on the surface

Question 24

1/2pV2 is most closely associated with

Answer 24

IAS

Question 25

The speed for max range will be higher/lower than the speed for max endurance

Answer 25

Always higher

Question 26

An aircraft is in straight and level flight at constant power. As weight reduces with fuel burn off, level flight may be maintained by .....

Answer 26

increasing the airspeed and lowering the nose. As fuel is burnt off weight is reduced, the nose needs to be lowered to allow lift to remain equal to the reducing weight. This means a reduction in drag, therfore more speed for the same power.

Question 27

**Flying for Endurance:** * Power - * Wind - * Speed - * Height - * Holding Rate -

Answer 27

* Power - Min power = min RPM * Wind - has NO effect * Speed - Fly @ speed for min power for any weight in any wind conditions * Height - Fly as low as possible * Holding Rate - Best settings with low FF providing good control effectiveness

Question 28

Describe "flying at min total drag speed" 5 different ways:

Answer 28

1. Fly @ most efficient AoA 2. Fly @ best lift/drag ratio 3. Fly @ best glide speed 4. Fly @ min thrust 5. Fly @ speed for best air nm

Question 30

**Lift = Cl1/2pV2S** V = .....?

Answer 30

Velocity

Question 31

Lift/Drag Ratio When flap is lowerd what happens to both the lift and drag .....

Answer 31

Both lift and drag increase

Question 32

Range & Endurance Compared with nil wind conditions a headwind component during cruise will result in ....

Answer 32

a reduction in range but no change in endurance

Question 32

Thrust v's speed graph: For an aircraft to achieve maximum endurance in level flight it must be flown at which speed ....

Answer 32

is slower than the bottom of this curve. Since the bottom of this curve represents min drag speed and the speed for min power is always less the speed to fly will be less than the point that represents speed S

Question 33

**Lift = Cl1/2pV2S** How does the pilot use the controls to manipulate Cl?

Answer 33

With the Elevators

Question 35

For 2 aircraft identical in every respect except for gross weight: To achieve max range in nil wind conditions both:

Answer 35

should find at the same AoA Since the heavier one needs to fly faster to maintain the AoA its speed would be greater

Question 37

An aircraft of a certain weight is flown at 150kts IAS at 1000ft. If the same aircraft was flown at 150kts IAS at 20,000ft, the AoA required to maintain level flight would be .....

Answer 37

The same

Question 38

For an aircraft at a particular gross weight, to maintain level flight at a particular height and IAS, a particular power setting is required. If gross weight is increased what happens to the AoA and the power setting .....

Answer 38

If weight is increased, drag will increase so a higher IAS will be required so a larger AoA and more power will be required.

Question 39

High wing loading is ideal for .....

Answer 39

Aircraft where high speed is involved

Question 40

Plain flaps have 3 main points, name them .....

Answer 40

1. increase camber 2. Small extensions are useful for lift 3. High drag when fully extended